全文获取类型
收费全文 | 16188篇 |
免费 | 95篇 |
国内免费 | 743篇 |
专业分类
安全科学 | 224篇 |
废物处理 | 1160篇 |
环保管理 | 1782篇 |
综合类 | 2535篇 |
基础理论 | 4828篇 |
环境理论 | 3篇 |
污染及防治 | 3762篇 |
评价与监测 | 1418篇 |
社会与环境 | 1199篇 |
灾害及防治 | 115篇 |
出版年
2023年 | 48篇 |
2022年 | 168篇 |
2021年 | 160篇 |
2020年 | 95篇 |
2019年 | 112篇 |
2018年 | 1657篇 |
2017年 | 1611篇 |
2016年 | 1537篇 |
2015年 | 333篇 |
2014年 | 315篇 |
2013年 | 429篇 |
2012年 | 1189篇 |
2011年 | 1867篇 |
2010年 | 953篇 |
2009年 | 855篇 |
2008年 | 1146篇 |
2007年 | 1501篇 |
2006年 | 265篇 |
2005年 | 555篇 |
2004年 | 659篇 |
2003年 | 578篇 |
2002年 | 238篇 |
2001年 | 120篇 |
2000年 | 96篇 |
1999年 | 102篇 |
1998年 | 72篇 |
1997年 | 65篇 |
1996年 | 39篇 |
1995年 | 48篇 |
1994年 | 33篇 |
1993年 | 22篇 |
1992年 | 30篇 |
1991年 | 19篇 |
1990年 | 24篇 |
1989年 | 18篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 12篇 |
1983年 | 8篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1972年 | 2篇 |
1967年 | 2篇 |
1966年 | 2篇 |
1958年 | 3篇 |
1935年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 890 毫秒
691.
Ma Hongxue Hu Guangchao Zhang Le Huo Xiangtao Guo Min Zhang Mei 《Journal of Material Cycles and Waste Management》2023,25(4):2222-2231
Journal of Material Cycles and Waste Management - This paper utilizes desulfurization ash (DA), fly ash (FA) and ordinary Portland cement (OPC) to prepare unfired high-strength road-base stones by... 相似文献
692.
Cristina E. Almeida-Naranjo Bryan Morillo María B. Aldás Nicole Garcés Alexis Debut Victor H. Guerrero 《补救:环境净化治理成本、技术与工艺杂志》2023,33(2):135-150
The removal of heavy metals from wastewater has become a global challenge, which demands the continuous study of efficient and low-cost treatment alternatives such as adsorption. In this research, the removal of zinc was evaluated using batch adsorption processes with nonconventional materials such as graphene oxide (GO), magnetite (MG), and their composites (GO:MG), formulated with three weight ratios (2:1, 1:1, and 1:2). Graphene was synthesized by the modified Marcano method, using pencil lead graphite as a precursor. MG and the composites were synthesized by chemical coprecipitation of ferrous sulfate and ferric chloride. The materials were characterized by Raman and Fourier transform infrared spectroscopies, scanning electron microscopy, X-ray diffraction, and the Brunauer–Emmett–Teller method to determine the functional groups, microstructural and morphological characteristics, and specific surface area. Batch adsorption tests were carried out to optimize the adsorbent dose and contact time with zinc solutions of 10 ppm. Zinc adsorption reached equilibrium at 2 h, with an optimal dose between 0.25 and 1.0 g/L. The maximum zinc removal efficiencies/adsorption capacities were 98.6%/165.6, 83.4%/47.6, 83.5%/21.9, 72.8%/19.9, and 82.2%/9.25 mg/g using GO, 2GO:1MG, 1GO:1MG, 1GO:2MG, and MG, respectively. Furthermore, the analysis of the isotherm and adsorption kinetics models determined that the adsorption processes using MG and the composites fit the Sips and pseudo-second-order models. 相似文献
693.
694.
BR-319: Brazil’s Manaus-Porto Velho Highway and the Potential Impact of Linking the Arc of Deforestation to Central Amazonia 总被引:3,自引:0,他引:3
Brazil’s BR-319 Highway linked Manaus, in the state of Amazonas, to Porto Velho, Rondônia, until it became impassable in 1988. Now it is proposed for reconstruction and paving, which would facilitate migration from the “Arc of Deforestation” in the southern part of the Amazon region to new frontiers farther north. The purpose of the highway, which is to facilitate transport to São Paulo of products from factories in the Manaus Free Trade Zone, would be better served by sending the containers by ship to the port of Santos. The lack of a land connection to Manaus currently represents a significant barrier to migration to central and northern Amazonia. Discourse regarding the highway systematically overestimates the highway’s benefits and underestimates its impacts. A variety of changes would be needed prior to paving the highway if these potential impacts are to be attenuated. These include zoning, reserve creation, and increased governance in various forms, including deforestation licensing and control programs. More fundamental changes are also needed, especially the abandonment of the long-standing tradition in Brazil of granting squatters’ rights to those who invade public land. Organizing Amazonian occupation in such a way that road construction and improvement cease to lead to explosive and uncontrolled deforestation should be a prerequisite for approval of the BR-319 and other road projects for which major impacts are expected. These projects could provide the impetus that is needed to achieve the transition away from appropriation of public land by both small squatters and by grileiros (large-scale illegal claimants). A delay in reconstructing the highway is advisable until appropriate changes can be effected. 相似文献
695.
Soil pollution with Cd is an environmental problem common in the world, and it is necessary to establish what Cd concentrations
in soil could be dangerous to its fertility from toxicity effects and the risk of transference of this element to plants and
other organisms of the food chain. In this study, we assessed Cd toxicity on soil microorganisms and plants in two semiarid
soils (uncultivated and cultivated). Soil ATP content, dehydrogenase activity, and plant growth were measured in the two soils
spiked with concentrations ranging from 3 to 8000 mg Cd/kg soil and incubated for 3 h, 20 days, and 60 days. The Cd concentrations
that produced 5%; 10%;, and 50%; inhibition of each of the two soil microbiological parameter studied (ecological dose, ED,
values) were calculated using two different mathematical models. Also, the effect of Cd concentration on plant growth of ryegrass
(Lolium perenne, L.) was studied in the two soils. The Cd ED values calculated for soil dehydrogenase activity and ATP content were higher
in the agricultural soils than in the bare soil. For ATP inhibition, higher ED values were calculated than for dehydrogenase
activity inhibition. The average yields of ryegrass were reduced from 5.03 to 3.56 g in abandoned soil and from 4.21 to 1.15
g in agricultural soil with increasing concentrations of Cd in the soil. Plant growth was totally inhibited in abandoned and
agricultural soils at Cd concentrations above 2000 and 5000 mg/kg soil, respectively. There was a positive correlation between
the concentration of Cd in the plants and the total or DTPA-extractable concentrations of Cd in the soil. 相似文献
696.
697.
利用废渣盐石膏制作轻型墙体材料 总被引:1,自引:1,他引:0
研究利用海盐化工产生的废渣盐石膏经过一定工艺处理,生产轻型墙体材料盐石膏空心条板,该产品与天然石膏空心条板相比,原料采用及生产工艺都有较大改进,生产成本却大幅度下降。经测试,该产品完全可替代天然石膏空心条板,技术性能指标达到了国家规定的相关标准。 相似文献
698.
699.
填埋场沼气发电的温室气体减排效益分析 总被引:2,自引:0,他引:2
填埋场沼气是垃圾卫生填埋场产生的可利用资源.以深圳下坪垃圾填埋场为例,定量分析垃圾填埋气体发电的温室气体减排效益.结果表明,填埋场沼气发电具有很好的经济效益和环境效益,可作为与发达国家进行CDM(清洁发展机制)项目合作的优先技术领域. 相似文献
700.
Environment, Development and Sustainability - The resource and environmental carrying capacity (RECC) is an important foundation and support for a city or region, and determines the direction of... 相似文献